Recent years have seen operations of transport networks, which enable failure recovery in the data plane without relying on the control plane. Nodes included in such a transport network are provided with OAM (Operation Administration and Maintenance) functions.
Patent Literature 1 discloses a technique that adopts GMPLS (Generalized Multi-Protocol Label Switching) as the control plane. According to Patent Literature 1, when failure recovery can be achieved by optical switches alone (the data plane in Patent Literature 1), the optical switches are switched. If failure recovery cannot be achieved by such optical switches alone, the GMPLS control plane is controlled to achieve failure recovery.
In addition, according to Patent Literature 2, when a failure occurs only in the control plane in a network in which the data plane and the control plane are formed by different media, disconnection of a path in the data plane during data forwarding is prevented.
Patent Literature 3 discloses a technique for efficiently achieving recovery of multiple failures and the like by distributed control.
Patent Literature 4 discloses a technique in which the data plane and the control plane are managed in coordination with each other. According to Patent Literature 4, reliable route status information is acquired by synchronizing the data plane and the control plane.    Patent Literature 1: Japanese Patent Kokai Publication No. JP2003-318983A    Patent Literature 2: Japanese Patent Kokai Publication No. JP2012-170161A    Patent Literature 3: Japanese Patent Kokai Publication No. JP2007-053793A    Patent Literature 4: Japanese Patent Kokai Publication No. JP2008-066989A